In case anyone missed it in the thread about Atlas returning to the York show, here's what Atlas posted:
Hi All,
Wanted to give some clarification - Atlas O Premier Locomotives are currently produced at MTH's old factory while Atlas O Master Locomotives are produced at Atlas' current O scale factory. MTH's factory is authorized and specializes in the installation and testing of the PS3 electronic components that are installed in the Atlas O Premier Locomotives. On the other side Atlas O's factory that produces O Master Locos specializes in the installation of Lionel's electronics.
For the current time Atlas O Master Locos will be offered and delivered with Lionel electronics and Atlas O Premier Locos will be offered and delivered with PS3 Electronics.
-Atlas O
Here's a link to the whole thread:
David